Local Treatment of Electron Correlation in Molecular Clusters: Structures and Stabilities of (H2O)n, n = 2−4
Local Treatment of Electron Correlation in Molecular Clusters: Structures and Stabilities of (H2O)n, n = 2−4
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分子簇中电子相关性的局部处理：(H2O)n, n = 2−4 的结构和稳定性
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
H. Werner
中科院分区：
文献类型：
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作者：
M. Schütz;G. Rauhut;H. Werner
用局域电子相关方法研究了小分子水团簇的结构和稳定性。结果表明，局部处理在很大程度上消除了基组叠加误差，从而实现了无基组叠加误差的几何优化。给出了不同基组的计算结果，结果表明，用局域二阶Moller−Plesset微扰理论(LMP2)计算的相互作用能和结构参数与未经平衡态修正的传统MP2结果基本一致。此外，还报道了(H2O)n(n=2−4)的LMP2能量被划分为不同的激发类，这强调了离子贡献和分子内关联对氢键团簇的重要性。将分析结果与对称适应微扰理论(SAPT)得到的数据进行了比较。
The structures and stabilities of small water clusters are studied by local electron correlation methods. It is demonstrated that the local treatment eliminates basis set superposition errors (BSSEs) to a large extent and thus allows BSSE-free geometry optimizations. Results for various basis sets are presented which show that the interaction energies and structural parameters obtained by local second-order Moller−Plesset perturbation theory (LMP2) without counterpoise correction are in close agreement with counterpoise-corrected conventional MP2 results. Furthermore, a partitioning of the LMP2 energies of (H2O)n, n = 2−4, into different excitation classes is reported, which underlines the importance of ionic contributions as well as intramolecular correlation for hydrogen-bonded clusters. The results of this analysis are compared with previous data obtained by symmetry-adapted perturbation theory (SAPT).